1. Field of the Invention
A grip for a golf club is made from an elastomeric material in a compression molding process wherein strips of the elastomeric material are placed in a compression mold around a mandrel. One of the strips, positioned at a location to form a portion of the length of the grip only on the undersurface of the grip at the butt end thereof, has exposed cords or fibers to improve gripping at that location of the grip. The completed grip therefore comprises an elongated hollow elastomeric sleeve adapted to fit over the butt end of a golf club shaft with a portion of the undersurface of the grip adjacent to the butt end of the grip having exposed cord.
2. Description of the Relevant Art
Grips for sporting implements such as golf clubs have taken numerous forms for many years with early grips consisting simply of a wrap of material, such as leather, in a helical pattern around the handle portion of the golf club. In recent years, the leather material has been replaced in some circumstances with polyurethane and rather than wrapping the polyurethane or leather strip of material directly onto the handle portion of the golf club, sometimes an elastomeric tubular underlisting is first mounted on the butt end of the golf club shaft so that the strip of leather or polyurethane material can be wrapped onto the underlisting.
Golf grips have evolved from the wrap type grip described above to vulcanized rubber sleeves that are simply slipped over the butt end of a golf club shaft. Such grips are still in use and typically made of one uniform elastomeric material. To improve the frictional gripping quality of the grip for the user of the club, a depressed pattern is frequently molded into the outer surface of the grip. Since the grip on a golf club must have a desired degree of torsional resistance, the elastomeric material from which the grip is made must be relatively hard which is sometimes undesirable from an aspect of obtaining the desired friction between the grip and the user""s hands. Further, hard rubber materials tend to become harder and slippery over time and when the grips become wet as when a golfer is playing in the rain.
Accordingly, in order to improve the friction between the grip and a user""s hand, particularly when the grip is wet, fibers or cords have been imbedded in the rubber so as to be partially exposed. U.S. Pat. No. 2,115,119 issued in 1938 to Park describes such a grip and a method of making the grip so that the cord is exposed substantially uniformly around the entire outer substantially cylindrical surface of the grip. Such grips have commonly been referred to as cord lined grips and have met with considerable success insofar as improving the friction between the grip and a user""s hands. Such grips have been criticized, however, as being overly abrasive thereby causing discomfort to a user""s hands and also premature wear to a golf glove used by a golfer.
It has later been recognized that the exposed cord on the top of the golf grip is not as important for friction purposes as it is along the bottom surface of the grip and accordingly a line of grips referred to as half-cord grips evolved which have exposed cord along the full length of the grip but only on the bottom half of the grip. The half-cord grips were acceptable from a friction standpoint but still were objectionable due to the abrasive nature of the cords particularly in the fingers of the hands which engaged the grip along the underside or bottom half of the grip.
The cord lined grips have been manufactured in substantially the same manner for a number of years with that process including embedding a fabric or layer of cotton fibers or the like within the rubber material from which the grip is molded and after the grip has been molded into the desired substantially cylindrical form having a hollow cavity for receiving the butt end of a golf shaft, the grip is subjected to sanding or another milling or grinding process for removing a thin outer layer of the rubber that overlies the cord until a desired amount of the cord is exposed while other portions of the cord remain imbedded in the rubber material of the grip.
While exposed cords in golf grips have provided some desirable improvements to the basic elastomeric rubber grip, both the full cord and half cord grip are still undesirable in being too abrasive on the fingers of both the left and right hands of a golfer.
Japanese Utility Model Patent No. 44525 discloses another form of a partial cord-lined grip wherein the exposed cord extends circumferentially around the entire grip but only along approximately half the length of the grip adjacent to the butt end of the grip. This grip is also not entirely satisfactory as the exposed cord on the top of the grip is not very necessary from a friction standpoint and creates unnecessary abrasion.
It is to overcome these shortcomings in the prior art that the grip of the present invention has been developed.
The present invention relates to an improved golf grip and a method of making same wherein the grip is predominately fabricated from strips of elastomeric rubber material but wherein one of the strips of material used to form the grip has a fiber or cord matting therein. The strip with the embedded fiber or cord matting is positioned in a compression mold so as to occupy only a portion of the lower half of a golf grip adjacent to the butt end of the grip as it has been determined that the most important portion of the grip providing friction between the grip and a golfer""s hands is in the fingers of the left hand for a right-handed golfer. For a right-handed golfer, the left hand is placed closer to the butt end of the grip than the right hand with the fingers overlying the bottom surface of the grip and by eliminating exposed cord on the top of the grip and along the bottom of the grip adjacent to the tip end of the grip, undesired and unnecessary abrasion to a user""s hand or golf glove can be avoided.
In other words, the grip of the present invention has been carefully designed to provide exposed cord only at the most important location on the grip for improving the friction between a golfer""s hand and the grip thereby minimizing abrasive issues that have existed in prior art grips.
The grip of the present invention can be manufactured in a compression molding process wherein the compression mold has two heated mold halves each having a matching and confronting recess in which the rubberized strips can be placed with a mandrel that occupies space that ultimately becomes the hollow core of the grip allowing it to be slid on the butt end of a golf club shaft. When fabricating the grip, a hard rubber plug is positioned in the cavity of the lower mold half adjacent to the butt end of the cavity. The cavity opens through the butt end of the mold to allow an assembly pin to retain the plug in desired alignment with the mandrel.
Before placing the mandrel in the cavity with the plug thereon, two strips of elastomeric material are laid in the lower mold half with the strip of material adjacent the tip end of the cavity being simply an elastomeric rubber material having a composition to be described in detail later and the strip of material adjacent the butt end of the cavity being an elastomeric rubber material having a fiber or cord fabric embedded therein. The strips of material placed in the lower half of the mold are preferably of substantially the same length even though variations in their length could be provided as desired. After the strips of material have been positioned in the lower mold half, the mandrel with the rubber plug mounted thereon is placed in the cavity in the lower mold half on top of the strips of material. Subsequently, an elongated strip of elastomeric rubber material identical to that of the strip adjacent the tip end of the cavity but having an overall length approaching that of the completed grip is laid on top of the mandrel. Finally, the upper half of the mold is positioned in overlying relationship with the lower half of the mold and they are compressed together and thereafter heated to a temperature sufficient to vulcanize the rubber in the cavity defined by the mold halves.
After vulcanization, the grip is removed from the cavity and de-flashed to remove excess rubber that results from the molding process. Thereafter, the substantially cylindrical outer surface of the grip is sanded or otherwise abrasively treated until the cord fabric in the rubber material adjacent the butt end of the grip on its undersurface is desirably exposed. After the sanding treatment, the outer surface of the grip is uniformly and desirably completed with cords exposed in the bottom surface of the grip adjacent its butt end where the fingers of the left hand (for a right-handed golfer) will engage the exposed cord to improve the friction between the grip and a user""s hands.
In one desired embodiment of the present invention, the elastomeric rubber material used in portions of the grip has small particles of cork interspersed therein that further enhance the frictional quality of the grip.